Jokes about creaky knees, thinning hair and spreading - or vanishing - waistlines have long been an inevitable, if unwelcome, part of watching the birthdays pile up.

But it shouldn't be that way, argues Wendy Lustbader, who maintains that youth, with all its insecurities and confusion, is more of a burden than the golden age society says it is, with ageing far from a gloomy decline.

"I'm so disgusted by the pervasive dread of ageing that everyone has, and the constant joking about it and everybody looking at later life as if it's just a dead zone, with nothing going on," said Lustbader, a former social worker and author who herself is in her late 50s.

"But it's really the opposite. When you really get to know elders, when you hang out with them as much as I have, it's the elders who really feel bad for the young people because they have so much suffering to go through."

To illustrate this somewhat unusual view, in the centrepiece of her recent book Life Gets Better Lustbader relates the story of telling a group of fellow travellers on a tour bus, most of whom were young, that they shouldn't worry because "these are the worst years of your lives."

Looks of obvious relief greeted this, and several of the young people later came up to her and confessed to having felt depressed and suicidal, but that her words helped.

"We are just in such dread, we just think this must be the good part and what's coming later must be terrible. Lots of things get hurt with that attitude," she said.

Lustbader argues, through a series of real-life examples from her years as a social worker and therapist, research findings and personal experience, that as people age they let go of a lot of the worries of their youth.

In addition, the experiences of life - both bad and good - teach acceptance and enjoyment of what people actually have, rather than what they might hope for, with priorities often shifting from material things to people.

"So many things that really seem to matter so much when you're younger just don't matter, and that's why we get so much freer ... All the elders talk about this sense of freedom," she said.

But not everyone manages to negotiate their later years with contentment. People who are too self-centred to build long-standing relationships may find themselves alone and unhappy, with Lustbader forced to include her own late mother in their number.

In addition, the ageism of many Western societies, where seniors are regarded with pity and often patronised - in contrast to the respect given them in places such as Mexico and Asian nations - makes things tough as well.

Lustbader also emphasises that she doesn't want to play down the undeniable physical difficulties of ageing, noting that losses in mobility and strength are losses that do have to be grieved.

This all leads ultimately to an almost Buddhist acceptance and added zest for the good in life because people also know about the bad.

"That's what a lot of older adults come to because of all the things they've been through," she said.

"There's so much about getting older that we can't know until we're there, the interior part of it. We only see the exterior when we're young, and we're fooled by that."